Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/db/migrations/postgres/000089_add-channelid-to-reaction.up.sql

@@ -0,0 +1,3 @@
+ALTER TABLE reactions ADD COLUMN IF NOT EXISTS channelid varchar(26) NOT NULL DEFAULT '';
+UPDATE reactions SET channelid = COALESCE((select channelid from posts where posts.id = reactions.postid), '') WHERE channelid='';
+CREATE INDEX IF NOT EXISTS idx_reactions_channel_id on reactions (channelid);